The present invention relates to a new and improved apparatus and method for use in positioning the femur and tibia of a leg relative to each other during surgery.
Although the apparatus and method of the present invention can be utilized during surgery in which a total knee replacement is undertaken, it is believed that the apparatus and method will be particularly advantageous for use during arthroscopic surgery in which unicompartmental knee replacement is undertaken. Using known apparatus and methods, surgeons tend to avoid unicompartmental knee replacement because of the accuracy with which bone cuts should be made and the time required to perform the surgery.
A known unicompartmental knee replacement system does not link the femur and tibia during surgery. Therefore, the surgeon makes his cuts independently and cannot obtain reproducible alignment of the femur and tibia. In addition, distraction of the joint cannot be obtained to correct for defects in the joint and to open the joint to facilitate surgery. This known system does not provide for correction of the transverse axis and/or mechanical axis of the joint.
A known system for unicompartmental knee replacement requires bone cuts to be made from the femoral component at 0.degree., 45.degree. and 90.degree. of leg flexion. Separate alignment, soft tissue balancing and measurement of each cut is required to determine the appropriate depth of cut. This is extremely time-consuming and very surgeon dependent. This procedure has been known to take over seven hours, even for a highly trained surgeon. This does not allow for tourniquet time or for any potential for the average or above average arthroscopic surgeon to perform such a difficult and time-consuming procedure.
The known system for unicompartmental knee replacement does not provide for distraction of the joint and appropriate restoration of the mechanical axis during surgery. Distraction of the joint is critical for improved visualization and for appropriate ligament balancing and releases. The aforementioned and other difficulties have resulted in surgeons tending to avoid unicompartmental knee replacements.
Although surgeons have, in the past, tended to avoid unicompartmental knee replacements, there are factors which favor this system. It is believed that a unicompartmental knee replacement provides for early rehabilitation of a patient with less trauma and pain. This will result in the patient's hospital stay being significantly shortened. In addition, scarring, adhesions and post-operative complications, which are common with open arthrotomy approaches, are avoided.